hostfs: don't keep a field in each inode when we are using it only in root

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 15 insertions, 24 deletions

diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index fab5f5a1e6f0..7e6750499b8b 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -19,7 +19,6 @@
 #include "kern.h"
 
 struct hostfs_inode_info {
-        char *host_filename;
         int fd;
         fmode_t mode;
         struct inode vfs_inode;
@@ -103,7 +102,7 @@ static char *dentry_name(struct dentry *dentry, int extra)
                 parent = parent->d_parent;
         }
 
-        root = HOSTFS_I(parent->d_inode)->host_filename;
+        root = parent->d_sb->s_fs_info;
         len += strlen(root);
         name = kmalloc(len + extra + 1, GFP_KERNEL);
         if (name == NULL)
@@ -266,7 +265,7 @@ int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf)
         long long f_files;
         long long f_ffree;
 
-        err = do_statfs(HOSTFS_I(dentry->d_sb->s_root->d_inode)->host_filename,
+        err = do_statfs(dentry->d_sb->s_fs_info,
                         &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
                         &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
                         &sf->f_namelen, sf->f_spare);
@@ -285,13 +284,10 @@ static struct inode *hostfs_alloc_inode(struct super_block *sb)
 {
         struct hostfs_inode_info *hi;
 
-        hi = kmalloc(sizeof(*hi), GFP_KERNEL);
+        hi = kzalloc(sizeof(*hi), GFP_KERNEL);
         if (hi == NULL)
                 return NULL;
-
-        *hi = ((struct hostfs_inode_info) { .host_filename      = NULL,
-                                            .fd                 = -1,
-                                            .mode               = 0 });
+        hi->fd = -1;
         inode_init_once(&hi->vfs_inode);
         return &hi->vfs_inode;
 }
@@ -308,14 +304,12 @@ static void hostfs_evict_inode(struct inode *inode)
 
 static void hostfs_destroy_inode(struct inode *inode)
 {
-        kfree(HOSTFS_I(inode)->host_filename);
         kfree(HOSTFS_I(inode));
 }
 
 static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 {
-        struct inode *root = vfs->mnt_sb->s_root->d_inode;
-        const char *root_path = HOSTFS_I(root)->host_filename;
+        const char *root_path = vfs->mnt_sb->s_fs_info;
         size_t offset = strlen(root_ino) + 1;
 
         if (strlen(root_path) > offset)
@@ -978,8 +972,8 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
                 req_root = "";
 
         err = -ENOMEM;
-        host_root_path = kmalloc(strlen(root_ino) + 1
-                                 + strlen(req_root) + 1, GFP_KERNEL);
+        sb->s_fs_info = host_root_path =
+                kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL);
         if (host_root_path == NULL)
                 goto out;
 
@@ -988,20 +982,13 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
         root_inode = hostfs_iget(sb);
         if (IS_ERR(root_inode)) {
                 err = PTR_ERR(root_inode);
-                goto out_free;
+                goto out;
         }
 
         err = init_inode(root_inode, NULL);
         if (err)
                 goto out_put;
 
-        HOSTFS_I(root_inode)->host_filename = host_root_path;
-        /*
-         * Avoid that in the error path, iput(root_inode) frees again
-         * host_root_path through hostfs_destroy_inode!
-         */
-        host_root_path = NULL;
-
         err = -ENOMEM;
         sb->s_root = d_alloc_root(root_inode);
         if (sb->s_root == NULL)
@@ -1019,8 +1006,6 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
 
 out_put:
         iput(root_inode);
-out_free:
-        kfree(host_root_path);
 out:
         return err;
 }
@@ -1032,11 +1017,17 @@ static int hostfs_read_sb(struct file_system_type *type,
         return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt);
 }
 
+static void hostfs_kill_sb(struct super_block *s)
+{
+        kill_anon_super(s);
+        kfree(s->s_fs_info);
+}
+
 static struct file_system_type hostfs_type = {
         .owner          = THIS_MODULE,
         .name           = "hostfs",
         .get_sb         = hostfs_read_sb,
-        .kill_sb        = kill_anon_super,
+        .kill_sb        = hostfs_kill_sb,
         .fs_flags       = 0,
 };